Sony and Toshiba, Are Competitors in the High Definition DVD

Sony and Toshiba, are competitors in the high definition DVD market. The products that they launched used different recording formats and were incompatible with each other. Given that Blu- ray, Sony's product, is now the dominant format for high definition films, which of the following is likely to be true?

A) Sony and Toshiba are likely to have colluded and set prices in the high definition DVD market.
B) The race to win market share between Sony and Toshiba is an example of a single-period
C) Sony is likely to have had a first-mover advantage in the market for high definition DVDs.
D) Sony and Toshiba must have agreed to split the market for high definition DVDs.